How To Find The Best Aquarium Thermometer

May 26, 2017

Maintaining the temperature of your aquarium is essential for the life of your fish or other water creature. Some fish thrive in cool water, while others (like tropical fish) thrive in warm water.

If you want to monitor the water temperature in your fish tank, then you need the best aquarium thermometer. With the many options available, you need to know the basics to help you get you get the right one.


Types of Aquarium Thermometers


Digital thermometers are the easiest to read because they have a digital display.

They are the priciest option, but it's because they are more hi-tech and convenient. But the difference in price is not very steep or significant, considering how easy and convenient they are to use.

There are many options of digital thermometers, but all include a probe and a digital display. The two can either have a wired or wireless connection. Some use batteries, while others plug into an outlet.


A standing or floating thermometer requires full submersion and can either be held in place or free floating. It has a conventional scale, which might be difficult to read.

However, manufacturers addressed this issue by using a different color for safe temperature range. That way, it'll be easy to spot if the temperature falls out of the ideal range.

If you are considering a standing/floating thermometer, then you should keep in mind the material it uses.

Many are made of glass which makes them a bit more fragile than digital or stick-on thermometers. There are plastic ones as well, but they might not be as accurate.

The advantage of standing or floating thermometers is that they are inexpensive. They also don’t require batteries or power. However, they aren't as accurate as digital thermometers, and they also don't have warning alarms.

If you have a standing or floating thermometer, then you need to make sure you can regularly check it.

Stick on

Stick-on thermometers are the kind you stick on the outside of the tank. Many have LCD displays, so they often call stick-on as LCD thermometers.

However, not all stick-on thermometers have LCD. Because they are placed outside of the fish tank, they're not very reliable. Factors like air conditioning, sunlight, or heaters can affect the reading.

What to look for in an aquarium thermometer


Accuracy is the most important factor to consider, so make sure that any outside factors (like room temperature) do not affect the readings. Digital thermometers are the most accurate kinds.


Make sure that the parts that need to be attached are easy to attach. Suction cups are the most common and the easiest kind of attachment.


Alarms are very useful because it will notify you if the temperature has gone out of range. This feature usually requires you to leave the probe in the tank for constant monitoring.

5 of the Best Aquarium Thermometers



Our Rating


Zacro Aquarium Thermometer

AODE® Digital LCD Aquarium Thermometer Fish Tank Water Terrarium Temperature

Marina Floating Thermometer

American Thermal Instruments Aquarium Thermometer

Leegoal Digital Aquarium Terrarium Fish Tank Thermometer(Black)

1. Zacro Aquarium Thermometer

Get it via Amazon

Being an Amazon number 1 best seller in Aquarium Thermometers should be a good enough reason to consider this thermometer. It lives up to the hype without breaking the bank.

The thermometer gives the most accurate reading within 0.1 of a degree. It comes with a submersible probe, an LCD monitor, and 3 inches of wiring to connect them both.


  • The most accurate temperature reading.
  • Widely used and the number 1 best selling, making it a very reliable option.
  • Affordable.
  • ​Can show readings in Fahrenheit or Celsius.


  • No backlighting on the LCD screen.
  • It doesn’t come with any warning alarms, should the temperature go out of range.

2. AODE® Digital LCD Aquarium Thermometer Fish Tank Water Terrarium Temperature

Get it via Amazon

The AODE Digital LCD Aquarium Thermometer is one of the best options there is. The battery-powered thermometer is 2 inches by 1.25 inches in size with a 3-foot cable that connects to the probe.

The temperature readings can be in Celsius or Fahrenheit and can show a range of -50 degrees to +70 degrees Celsius.


  • It has very accurate temperature readings.
  • The display is very easy to read because of the large numbers.
  • It’s great quality at an affordable price.
  • ​It has a long battery life. You can even extend it more by turning off the display.
  • ​Suction and probe don’t are distracting.


  • No alarms
  • No backlight on display so it can be difficult to read in the dark.

3. Marina Floating Thermometer

Get it via Amazon

The Marina Floating Thermometer is a standing/floating kind of aquarium thermometer. It comes with a suction cup so you can stick it to the aquarium wall.

Reading the temperature is quite easy because of the bright red liquid indicator. It also has a safety zone indicator, so it’s easy to spot out of range readings.


  • It’s inexpensive.
  • The display is pretty easy to read.
  • Comes with suction cups.
  • Widely used, which indicates that it’s pretty decent quality for it’s kind.


  • For large tanks, you might need more than one thermometer.
  • It’s very basic. This kind of thermometer doesn’t come with alarms or aren’t as accurate as digital thermometers do.

4. American Thermal Instruments Aquarium Thermometer

Get it via Amazon

The American Thermal Instruments Aquarium Thermometer is a horizontal stick on thermometer. It uses a liquid crystal that changes colors to temperature.

To use it, select an area outside the fish tank that’s below the waterline, then remove the release paper to expose the adhesive.

Then, stick it on firmly in place. The back of the thermometer will sense the temperature, and it will reflect on the thermometer display.


  • It’s very easy to use.
  • You can peel it off easily and put in another area of the tank.
  • The display is very easy to read and understand.


  • It’s accurate for its kind but not as accurate as the other kinds of thermometers.
  • For the price, you can get a more accurate standing/floating thermometer.

5. Leegoal Digital Aquarium Terrarium Fish Tank Thermometer(Black)

Get it via Amazon

The Leegoal Digital Aquarium Terrarium Fish Tank Thermometer is another great option for those looking for a digital display. It has an easy to read LCD which you can stick on with a suction cup.

The probe detects the temperature of the water and translates the results in either Fahrenheit or Celsius. However, make sure the display doesn't get wet because it's not waterproof.


  • 3 feet of insulated wire that connect the probe to display.
  • Easy to use and setup
  • Celsius and Fahrenheit readings.
  • Cheap.


  • Not the best of its kind.
  • Lack of backlighting makes the reading difficult to see.
  • No alarms or warning signs to indicate that the temperature is out of range.


Aquarium thermometers are an essential tool for fish and tank owners because it tells the water temperature. This is because you always need to keep the water temperature at levels suitable for the fish.

There are three basic kinds to choose from - digital, standing/floating, and stick-on. But the most accurate kinds are the digital thermometers.

The digital thermometers here are very similar, and they’re all pretty good options. However, if I had to choose one, it’d have to be the Zacro LCD Digital Aquarium Thermometer. The display is just slightly better than the other options. Plus, the fact that it is the number 1 bestseller makes it more trustworthy.

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